Build 5608 "Enable Virtual Memory Allocation" Problem - Help!

After working fine earlier today, receiving this message now:

Parallels Desktop failed to allocate the specified amount of memory.
Please restart Parallels Desktop and try again.
To avoid this problem in the future choose from the menu: Parallels Desktop > Preferences. On the Memory tab select the "Enable virtual memory preallocation" option.

I have been running version 5608 for months with no problems, including earlier this morning, but now it won't do anything. I have a big presentation tomorrow and would prefer not to have to go to Boot Camp with the re-registration required on the switch-over.

EDIT: Following the instructions above does nothing...

Here is my machine (running Windows XP on the VM):

Model Name: MacBook Pro
Model Identifier: MacBookPro4,1
Processor Name: Intel Core 2 Duo
Processor Speed: 2.5 GHz
Number Of Processors: 1
Total Number Of Cores: 2
L2 Cache: 6 MB
Memory: 2 GB
Bus Speed: 800 MHz
Boot ROM Version: MBP41.00C1.B00

Any help is greatly appreciated!

 

Your Mac Memory is fragmented. Run your maintenance tasks in MacOSX, and reboot. Fixed.

 

Sorry for such a noob question, but what exactly do I do for this...

TIA